Silicon U-shaped carrier members are conventionally mounted upright in the interior of a reaction vessel, electrically heated, and subjected to silicon deposition over outer surfaces thereof. Though in the past such U-shaped carrier members have been commonly made of two spaced, parallel, equally sized straight rod sections interconnected by a third rod section mounted across the upper ends thereof, recently a general process has been discovered whereby a single straight starting rod of silicon can be bent directly in a U-shaped carrier member in such a manner that the product member is surprisingly uniformly electrically heatable. See co-pending application Ser. No. 629,916, now U.S. Pat. No. 4,012,217, filed on Nov. 7, 1975 herewith. However, the art still needs an optimized, mechanized, reliable, automatable technique suitable for bending initially straight silicon rods into desired U-shapes.